As far as I can tell one can obtain Russian citizenship but I can't find a procedure on how. One way is through marriage but are there any others?
Since the political-related comments have been removed, I'll refrain from suggesting your friend to move to Crimea.
Other than that - here are the rules. I won't quote since they actually change quite frequently (the latest change was a couple of weeks ago). You can always find the up-to-date information at UFMS websites. Warning - it's in Russian. Apparently, being fluent in Russian is a prerequisite for naturalization.